Katsumi Bakugo is a 17-year-old girl who has big problems with math. Her mother Mitsuki decided to sign her up for tutoring, which of course Katsumi didn't like. A rebellious young girl decides to be as malicious as possible so that the person giving her tutoring will quit.

When the day of first lesson finally arrives and Katsuki goes to tutoring, he finds a grown-up, sweet woman named Izumi Midoryia. Katsumi suddenly learns that she prefers women, and this one particularly caught her eye. The only obstacle is the woman's age, she is 10 years older than her.

Will everything turn out fine? Will Katsumi be able to make a beautiful woman fall in love with him?